When the rotorcraft is in the flight configuration, its blades are connected to the hub of the main rotor via fastener means that lock them in a deployed position.
In order to fold a blade, it is then necessary to unlock the blade so as to allow it to move through a large amplitude, generally towards the rear.
To deploy a blade, it suffices to perform the above-specified sequence in reverse order. The blade is returned to the flight configuration by moving through a large amplitude, generally towards the front, and it is then locked in the deployed position.
A first device for folding/deploying a blade is known that makes use of two single-outlet motors respectively for performing the locking function and for performing the folding function via first and second transmissions of movement. Each single-outlet motor comprises an outer casing surrounding a stationary stator provided with a coil, and having a rotor located therein. On being powered electrically, the stator creates magnetic field that causes the rotor to rotate, which can then drive the transmission to which it is connected.
That solution is effective, but bulky and difficult to implement.
A second device is known for folding/deploying a blade, referred to as an “interlock” device, that uses a single motor having a single outlet that controls both the locking/unlocking mechanism and the folding/deploying mechanism. Depending on the position of the fastener means, and acting via “mechanical” logic linked to the transmissions, either the locking/unlocking mechanism or the folding/deploying mechanism is driven. Although apparently advantageous, that second device is very difficult to develop and its weight is high, given the large number of mechanical parts.
As mentioned above, known devices require two different transmissions to be driven, in order to fold/deploy the blades of the main rotor of a rotorcraft, for example, making use of one or two motors each having a single outlet. Under such conditions, in order to avoid the above-mentioned limitations associated with those prior art devices, it is appropriate to make use of a new kind of motor, referred to below as a two-outlet motor, for actuating the two transmissions of movement.